Unclear restrictions on properties when instantiating metaClass: Class

Question

In section 9.3.3 (Constraints) of the MOF 2.5.1 specification the following conditions are listed in order to instantiate a metaClass: Class:

[4] Property: 0 <= LowerBound <= UpperBound required. [5] Property: 1 <= UpperBound required. [9] Property: Container end must not have upperBound >1, a property can only be contained in one container.

I dont understand what is meant by [4] and [5], and with [9] ChatGPT gave me below example:

class Department {
  attribute name: String;
  reference employees: Employee[*];  -- employees are contained in the Department
}

class Employee {
  attribute name: String;
  reference department: Department;  -- reference to the container (Department)
}

The employees reference in the Department class represents the container end. It has an upper bound * (unbounded), indicating that a department can contain multiple employees, and this adheres to the constraint “Container end must not have upperBound >1.” Here, the upper bound is not greater than 1; it is unbounded, allowing for any number of employees.

In this age of alternate facts this should make sense, but I’m from the time before so can someone please logically explain what is meant by [4],[5] and [9]?